Nanomechanics of Ultrathin Metallic Nanowires and Their Scalable Assembly

Project: Research

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As the critical feature sizes of modern electronic devices continue to shrink, extensiveresearch has been focused on the development and implementation of next-generationinterconnects in order to incorporate increasingly small feature sizes with highperformance and reliability in a cost-effective manner. Existing top-down fabricationtechniques (e.g. photolithography) will expect to encounter a barrier for characteristiclengths below 14 nanometers (nm). Ultrathin metallic nanowires, on the other hand,which made by bottom-up chemical synthesis, as a new kind of one-dimensional (1-D)metallic nanostructures with diameters less than 10nm, have recently emerged as idealcandidates for future nanoelectronics applications at sub-10nm level.Since the first reports on rational synthesis of ultrathin gold (Au) nanowires in 2008,more and more ultrathin metallic nanowires (Pt, Pd, AuAg, FePtPd…) with well-controlledcrystalline structure and morphology have been recently fabricated andreported, which could have great potential not only for integrated-circuits (IC) industry,but also in many other fields such as energy conversion, catalyst, and bio-sensorsbecause of their unique physical properties. Nevertheless, all these attractiveapplications requires a comprehensive understanding of their mechanical performanceand reliability, as both theoretical predictions and our preliminary experimental study onultrathin Au nanowires indicated that the deformation mechanisms will be radicallydifferent to those larger nanowires with hundreds of nanometers. So in this project, wewill develop and use our customized in situ SEM/TEM platforms for quantitativenanomechanical characterization of various ultrathin metallic nanowires. Furthermore,we will study their electro- and thermo-mechanical responses under charging andheating, respectively, to simulate how these 1-D building blocks degrade in realisticserving conditions.Another major challenge that hinders the industrial application of ultrathin metallicnanowires is bottom-up assembly. Despite that significant progresses had been made inhierarchical assembly and joining of traditional nanowires, the nature of ultrathinnanowires determines that they require special handling techniques on alignment andintegration, to prevent any potential damage. Therefore in this project, we propose toadopt pure mechanical alignment approaches based on the “Langmuir?Blodgett”, “strainreleasing” and “nano-combing” methods, assisted with our earlier discovered “coldwelding” integration technique, for the scalable assembly of ultrathin metallic nanowires.The successful implementation of this project will not only provide comprehensiveunderstanding of the intrinsic mechanical properties of ultrathin metallic nanowires aswell as their mechanical responses under service conditions, but also provide a feasibleassembly technique for scalable integration of ultrathin metallic nanowires for futurenanoelectronics and many other applications.


Project number9042051
Grant typeGRF
Effective start/end date1/01/1518/06/19

    Research areas

  • nanomechanics,ultrathin metallic nanowires,size effect,in situ electron microscopy,